1: Start by grating the cheese and the mushroom on the fine side of a box grater, then roughly slice up the tomato.

2: Crack the egg onto a plate and add the milk and cayenne pepper, then beat with a fork to combine it all together. Dip the slices of bread into the eggy mixture so that each piece soaks up the egg and milk. 

3: Heat the vegetable oil in a frying pan over a medium heat and, once hot, add the slices of bread to the pan and gently fry for a few minutes until browned on one side. Flip the slices over and cook the other side for a few more minutes.

4: Pop the grated cheese, mushroom and tomato on top of one of the slices of bread, and then place the other slice on top. Squash the sandwich together with the back of a spatula and cook gently for a few more minutes until the cheese has melted.

5: Lift the butty onto a plate and slice in half before tucking in.